Marcus Smith's rapid rise shows no signs of slowing down – it took barely a year for him to go from captaining Brighton College in an unbeaten season to involvement in the senior England squad. Smith became the second-youngest Premiership debutant in history, behind George Ford, when making his Harlequins bow against London Irish aged 18 years and 200 days in September 2017. He was named as an apprentice in the England party for the Old Mutual Wealth series that autumn and continued in that role during the 2018 Guinness Men's Six Nations. He made his Test debut in 2021 against the USA and contributed 13 points, including a try, to their 43-19 victory. In 2021 he was called up to the British & Irish Lions squad and kicked all seven conversions in their game against the Stormers. Smith featured in Steve Borthwick’s squad for the 2023 Rugby World Cup in France, playing at both fly half and full back. He played in the Summer Series tour of Japan and New Zealand, and was recently named in Borthwick's squad for the 2025 Six Nations.